Canvas stretching frame



May 19, 1964 H. P. MYREN CANVAS STRETCHING FRAME Filed Feb. 16, 1961 ends of the strips.

United States Patent 3,133,375 CANVAS STRETCHING FRAME Holger Patn'k Myrn, Tranas, Sweden, assignor to Aktiebolaget Tranas Guldlistfabrik, Tranas, Sweden, a joint-stock company of Sweden Filed Feb. 16, 1961, Ser. No. 89,758

3 Claims. (Cl. 45-130) This invention relates to improvements in canvas stretching frames. One object of the invention is to provide such a frame, composed of separable strips for stretching canvas paintings, the ends of said strips being mitered at the front side, which strips may be forced uniformely apart by wedges driven in between adjoining ends of the strips essentially parallel to the mitered edges.

Another object of the invention is to provide a device of the above-mentioned character which is simple and durable in construction, reliable and efiicient in use and inexpensive to manufacture.

Other objects and advantages of the invention will be apparent during the course of the following description.

-In the accompanying drawing, forming a par-t of this specification and in which like numerals are employed to designate like parts throughout the same.

FIG. 1 is a plane view of the front side of the frame,

FIG. 2 is a plane view of the back side of the frame,

FIG. 3 is an enlarged scaled plane view of the front side of the upper left corner portion of the frame,

FIG. 4 is an edge view seen from the left hand and FIG. 5 is an edge view seen from above of the corner portion as shown in FIG. 3,

FIG. 6 is an inner edge view of one strip of the frame and FIGS. 7 and 8 are perspective views of the end portions of the strips as visible in FIG. 3 before their joining.

-In the drawing, whereinfor the purpose of illustration I have shown a preferred embodiment of my invention, the frame consists of four strips 1, the ends of which are mitered at their front side as at 4 and preferably under an angle of 45. Each of said mitered ends has a tongue 5 and groove 7 for interlocking engagement with the ends of adjoining strips, said tongues having edges 6, which are parallel to the longitudinal marginal edges of the strip in question. The frontface of each strip has a bead 2 along its marginal outer edge, over which the canvas extends when stretched, and within said. head the front face has a milled down portion 3. The canvas 11 is secured to the frame by any securing means such as tacks 12.

In the mitered edges of the strips grooves 8 are provided for wedges 9 for the forcing apart of adjoining The inner surface of each groove 8 is forming a less angle with the longitudinal edges of the strip than the mitered edge 4, so that by a wedge with a corresponding wedge angle driven in such a groove with an edge contacting said inner surface and another edge contacting either the mitered edge 4 of the adjoining strip or a corresponding wedge in said adjoining strip just in front of said first mentioned wedge the two strips may be uniformly driven somewhat apart in order to have the canvas stretched.

Naturally the two strips may also be forced somewhat apart by only one wedge with the double wedge angle driven in two grooves 8 facing each other in the adjoining strips.

An advantage with the mitered edges of the strips is that the strips can be sawn olf in desired lengths from long strips provided with a bead 2' along one marginal 3,133,375 Patented May 19, 1964 edge, whereby the ready frame obtains such beads along its marginal outer edges.

Having thus described my invention, I claim:

1. A canvas stretching frame comprising a plurality of separate strips, each of said strips being mitered at their remote ends, said strips being further provided with head structure extending longitudinally along their length, said mitered ends of said strips being provided with a complementary tongue and groove structure at their front and rear faces for locking interengagernent of the ends of the strips together in perpendicular relation to one another to form corners, each of said strips being further provided with wedge grooves adjacent said tongue and groove structure for forcing the strips apart in a perpendicular direction to the adjoining mitered edges, when the wedges are introduced into the grooves, said wedge grooves being formed in said mitered ends at a tapered, ever increasing angle relative to the mitered edge, facilitating the introduction of a wedge into said grooves and accommodating the wedging action, said wedge grooves converging toward one another along an axis diagonal to the length of the perpendicular converging remote ends of said strips, a pair of wedges introducible into the wedge grooves of each of said corners, said pair of wedges having their inner opposingsurfaces parallel with one another and having their outer opposing surfaces tapered relative to one another to conform to the taper of said wedge grooves, each of said wedges being individually movable relative to the other to independently adjust and separate the strips apart at their remote ends for stretching.

2. A canvas stretching frame comprising a plurality of separate strips, each of said strips being mitered at their remote ends, said strips being further provided with bead structure extending longitudinally along their length, said mitered ends of said strips being provided with a 1 complementary tongue and groove structure at their front and rear faces for locking interengagernent of the ends of the strips together in perpendicular relation to one another to form corners, each of said strips being further provided with wedge grooves adjacent said tongue and groove structure for forcing the strips apart in a perpendicular direction to the adjoining mitered edges, when the wedges are introduced into the grooves, said wedge grooves being formed in said mitered ends at a tapered, ever increasing angle relative to the mitered edge, facilitating the introduction of a wedge into said grooves and accommodating the wedging action, wedge means including a wedge having an angle along one side similar to one of the wedge grooves and facing the bottom of said groove and including a separate surface in the adjoining strip which is parallel to the mitered end of said strip and to the other side of said wedge.

3. A canvas stretching frame according to claim 2, wherein said separate surface in the adjoining strip comprises a smiliar wedge.

References Cited in the file of. this patent UNITED STATES PATENTS 133,707 Hutchinson Dec. 10, 1872 944,601 Davison Dec. 28, 1909 1,847,925 Carter Mar. 1, 1932 1,870,492 Clark Aug. 9, 1932 !1,916,022 Shull i June 27, 1933 2,601,734 Couzinet July 1, 1952 2,633,653 Angus Apr. 7, 1953 FOREIGN PATENTS 370,506 Germany June 7, 1923 

1. A CANVAS STRETCHING FRAME COMPRISING A PLURALITY OF SEPARATE STRIPS, EACH OF SAID STRIPS BEING MITERED AT THEIR REMOTE ENDS, SAID STRIPS BEING FURTHER PROVIDED WITH BEAD STRUCTURE EXTENDING LONGITUDINALLY ALONG THEIR LENGTH, SAID MITERED ENDS OF SAID STRIPS BEING PROVIDED WITH A COMPLEMENTARY TONGUE AND GROOVE STRUCTURE AT THEIR FRONT AND REAR FACES FOR LOCKING INTERENGAGEMENT OF THE ENDS OF THE STRIPS TOGETHER IN PERPENDICULAR RELATION TO ONE ANOTHER TO FORM CORNERS, EACH OF SAID STRIPS BEING FURTHER PROVIDED WITH WEDGE GROOVES ADJACENT SAID TONGUE AND GROOVE STRUCTURE FOR FORCING THE STRIPS APART IN A PERPENDICULAR DIRECTION TO THE ADJOINING MITERED EDGES, WHEN THE WEDGES ARE INTRODUCED INTO THE GROOVES, SAID WEDGE GROOVES BEING FORMED IN SAID MITERED ENDS AT A TAPERED, EVER INCREASING ANGLE RELATIVE TO THE MITERED EDGE, FACILITATING THE INTRODUCTION OF A WEDGE INTO SAID GROOVES AND ACCOMMODATING THE WEDGING ACTION, SAID WEDGE GROOVES CONVERGING TOWARD ONE ANOTHER ALONG AN AXIS DIAGONAL TO THE LENGTH OF THE PERPENDICULAR CONVERGING REMOTE ENDS OF SAID STRIPS, A PAIR OF WEDGES INTRODUCIBLE INTO THE WEDGES GROOVES OF EACH OF SAID CORNERS, SAID PAIR OF WEDGES HAVING THEIR INNER OPPOSING SURFACES PARALLEL WITH ONE ANOTHER AND HAVING THEIR OUTER OPPOSING SURFACES TAPERED RELATIVE TO ONE ANOTHER TO CONFORM TO THE TAPER OF SAID WEDGE GROOVES, EACH OF SAID WEDGES BEING INDIVIDUALLY MOVABLE RELATIVE TO THE OTHER TO INDEPENDENTLY ADJUST AND SEPARATE THE STRIPS APART AT THEIR REMOTE ENDS FOR STRETCHING. 